With the development of wireless communications, various kinds of communication devices have been installed in vehicles, including radios, navigation, DMB, etc.; and for these devices, antennas also have to be mounted.
As numerous antennas have thus come to be installed on the inside and outside of vehicles, because of the vehicle's shielding effect tending to reduce the reception rate for internal antennas, antennas have been mounted on the outside of the vehicle, and external antennas in the shape of a shark fin, which is an attractive shape with low air resistance, have attracted growing attention.
Generally, shark-fin antennas consist of ceramic-chip-type GPS antennas, fixed to a base, and AM/FM/DMB antennas in a coil or PCB shape.
However, with the recent growth in multimedia, as demand has arisen for “infotainment” services in which information can be gathered while in the vehicle, a need has arisen for a plurality of antennas that can support such services, such as GSM, LTE, WiFi, AM, and FM antennas.
Apart from AM/FM and WiFi antennas, LTE antennas in particular require at the same time both a main antenna and a diversity antenna, and only when the interference between these two antennas is minimized is the data transmission speed good and data distortion reduced.
However, previously, when the two kinds of LTE antennas (main, diversity) have been added in the narrow interior of the sharkfin antenna, especially in the low frequency band (700 MHz-1 GHz), signal interference has been severe, leading to data distortion and impaired data transmission speed.
In addition, the problem has arisen of the limitations on the size to which the sharkfin antenna mounted on the exterior of a vehicle can grow, in view of the need to keep all of the antennas covering a plurality of frequency bands within a single sharkfin antenna.
In addition, as electric power has been supplied by soldering the antenna contacts to a circuit board, there has been the problem of power supply and inadequate electrical contact at the solder sites due to external impact.
Patent Reference: Republic of Korea Registered Patent Gazette No. 10-0843150 (issued 2008 Jul. 2)